CN109791331B

CN109791331B - Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element

Info

Publication number: CN109791331B
Application number: CN201780060704.XA
Authority: CN
Inventors: 金尔润; 中原翔一朗; 桥本淳
Original assignee: Nissan Chemical Corp
Current assignee: Nissan Chemical Corp
Priority date: 2016-09-29
Filing date: 2017-09-28
Publication date: 2022-05-27
Anticipated expiration: 2037-09-28
Also published as: TW201829751A; CN109791331A; TWI750233B; JPWO2018062440A1; WO2018062440A1; KR20190058570A; KR102465494B1; TW202212421A; JP7089231B2

Abstract

A liquid crystal aligning agent, comprising: (A-1) at least 1 polymer selected from the group consisting of polyamic acid obtained by using a tetracarboxylic dianhydride component comprising a tetracarboxylic dianhydride represented by the following formula (1) and a diamine component comprising a diamine represented by the following formula (2), and an imidized polymer of the polyamic acid; (A-2) at least 1 polymer selected from the group consisting of polyamic acid obtained by using a tetracarboxylic dianhydride component containing an aliphatic tetracarboxylic dianhydride and a diamine component containing a diamine represented by the following formula (2), and an imidized polymer of the polyamic acid; (B) at least 1 polymer selected from the group consisting of a polyimide precursor, an imidized polymer of the polyimide precursor, and a photosensitive side-chain acrylic polymer exhibiting liquid crystallinity in a specific temperature range; and an organic solvent.

Description

Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element

Technical Field

The present invention relates to a liquid crystal aligning agent and a liquid crystal alignment film for a liquid crystal display element, and a liquid crystal display element using the same.

Background

Liquid crystal devices have been widely used as display units for personal computers, mobile phones, television receivers, and the like. The liquid crystal device includes, for example: a liquid crystal layer interposed between the element substrate and the color filter substrate, a pixel electrode and a common electrode for applying an electric field to the liquid crystal layer, an alignment film for controlling alignment of liquid crystal molecules in the liquid crystal layer, a Thin Film Transistor (TFT) for converting an electric signal supplied to the pixel electrode, and the like. As a driving method of liquid crystal molecules, a longitudinal electric field method such as a TN method and a VA method; a lateral electric field system such as an IPS system or a boundary electric field switching (hereinafter, referred to as FFS) system (for example, patent document 1).

In recent years, however, the liquid crystal display element and the organic EL element are also economically important in the production process, and therefore, the recycling of the element substrate is required. That is, when defects occur due to inspection of alignment properties or the like after forming a liquid crystal alignment film from a liquid crystal alignment agent, it is required that a rework process of removing the liquid crystal alignment film from a substrate and recovering the substrate can be easily performed. However, the liquid crystal alignment film obtained from the liquid crystal aligning agent proposed in the related art is intended to be insoluble in an organic solvent or the like after post-baking and to reduce film loss. Even if the liquid crystal aligning agent composition, which has been studied for reworkability, is used as it is for the liquid crystal aligning agent for a transverse electric field, the desired object cannot be achieved, and it is necessary to actually evaluate whether the liquid crystal aligning agent has excellent reworkability again and to investigate the optimum composition configuration again.

In addition, liquid crystal display elements are now widely used as display devices. A liquid crystal alignment film, which is a component of a liquid crystal display element, is a film for uniformly aligning liquid crystals, but various properties are required in addition to the alignment uniformity of liquid crystals. For example, in a process for producing a liquid crystal alignment film, an alignment treatment such as brushing in which the surface of a polymer film is wiped with a cloth is generally performed. However, when the liquid crystal alignment film has insufficient abrasion resistance, the film is scraped to cause scratches or dust, or the film itself is peeled off, which deteriorates the display quality of the liquid crystal display element. Further, a voltage is applied to the liquid crystal to drive the liquid crystal display element. Therefore, when the Voltage Holding Ratio (VHR) of the liquid crystal alignment film is low, a sufficient voltage cannot be applied to the liquid crystal, and the contrast ratio is lowered. Further, when charges are accumulated in the liquid crystal alignment film by a voltage for driving the liquid crystal or it takes time to escape the accumulated charges, a phenomenon such as image sticking or an afterimage may occur.

As products that satisfy some of such required characteristics as described above at the same time, various proposals have been given. For example, patent document 2 proposes a method for obtaining a liquid crystal alignment film having excellent rubbing resistance and little image sticking and afterimage. Patent document 3 proposes a liquid crystal alignment film having excellent liquid crystal alignment properties, alignment controllability, and rubbing resistance, a high voltage holding ratio, and reduced charge accumulation.

Documents of the prior art

Patent literature

Patent document 1: japanese patent laid-open publication No. 2013-167782

Patent document 2: international publication WO02/33481 booklet

Patent document 3: international publication WO2004/053583 pamphlet

Disclosure of Invention

Problems to be solved by the invention

The invention aims to provide a liquid crystal aligning agent which can obtain a liquid crystal aligning film which meets various characteristics required by the liquid crystal aligning film and has excellent reworkability.

Means for solving the problems

As a result of intensive studies to solve the above problems, the present inventors have found that a liquid crystal alignment film satisfying various properties required for a liquid crystal alignment film and having excellent reworkability can be obtained by using a polyamic acid and an imidized polymer of a polyamic acid obtained from a tetracarboxylic acid containing a specific aromatic tetracarboxylic dianhydride and an aliphatic tetracarboxylic dianhydride and a diamine having a specific structure, and have completed the present invention.

The present invention is thus based on the above findings, and has the following gist.

1. A liquid crystal aligning agent, comprising:

(A-1) at least 1 polymer selected from the group consisting of polyamic acid obtained by using a tetracarboxylic dianhydride component comprising a tetracarboxylic dianhydride represented by the following formula (1) and a diamine component comprising a diamine represented by the following formula (2), and an imidized polymer of the polyamic acid;

(A-2) at least 1 polymer selected from the group consisting of polyamic acids obtained by using a tetracarboxylic dianhydride component comprising an aliphatic tetracarboxylic dianhydride and a diamine component comprising a diamine represented by the following formula (2), and imidized polymers of the polyamic acids;

(B) at least 1 polymer selected from the group consisting of a polyimide precursor, an imidized polymer of the polyimide precursor, and a photosensitive side-chain acrylic polymer exhibiting liquid crystallinity in a specific temperature range; and

an organic solvent.

(in the formula (1), i is 0 or 1, X is a single bond, ether bond, carbonyl, ester bond, phenylene, C1-20 linear alkylene, C2-20 branched alkylene, C3-12 cyclic alkylene, sulfonyl, amido bond or a group formed by combination of the above, wherein the C1-20 alkylene is optionally interrupted by a bond selected from ester bond and ether bond, and the carbon atoms of the phenylene and the alkylene are optionally substituted by 1 or more same or different substituents selected from halogen atom, cyano group, alkyl group, halogenated alkyl group, alkoxy group and halogenated alkoxy group.

In the formula (2), Y₁Is a 2-valent organic group having at least 1 structure selected from the group consisting of amino groups, imino groups and nitrogen-containing heterocyclic rings, B ₁、B₂Each independently represents a hydrogen atom, or an optionally substituted alkyl, alkenyl or alkynyl group having 1 to 10 carbon atoms. )

2. The liquid crystal aligning agent according to 1, wherein 10 to 100 mol% of the tetracarboxylic dianhydride component of the above (A-1) is the tetracarboxylic dianhydride of the formula (1).

3. The liquid crystal aligning agent according to 1 or 2, wherein 10 to 100 mol% of the tetracarboxylic dianhydride component of the (A-2) is an aliphatic tetracarboxylic dianhydride.

4. The liquid crystal aligning agent according to any one of claims 1 to 3, wherein 10 to 100 mol% of the diamine components (A-1) and (A-2) is a diamine of the formula (2).

5. The liquid crystal aligning agent according to any one of claims 1 to 4, wherein Y in the formula (2)₁Is at least 1 selected from the following structures of formulas (YD-1) to (YD-5).

(in the formula (YD-1), A₁Is a nitrogen atom-containing heterocycle having 3 to 15 carbon atoms, Z₁Is a hydrogen atom or an optionally substituted hydrocarbon group having 1 to 20 carbon atoms. In the formula (YD-2), W₁Is a C1-10 hydrocarbon group, A₂Is a C3-15 organic group having a nitrogen atom-containing heterocycle, or a disubstituted amino group substituted with a C1-6 aliphatic group. In the formula (YD-3), W₂A C6-15 and a 2-valent organic group having 1-2 benzene rings, W ₃Is C2-5 alkylene or biphenylene, Z₂Is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a benzene ring, and a is an integer of 0 to 1. In the formula (YD-4), A₃Is a nitrogen atom-containing heterocycle having 3 to 15 carbon atoms. In the formula (YD-5), A₄Is a C3-15 nitrogen atom-containing heterocycle, W₅Is an alkylene group having 2 to 5 carbon atoms. )

6. The liquid crystal aligning agent according to claim 5, wherein A is represented by the formulae (YD-1), (YD-2), (YD-4) and (YD-5)₁、A₂、A₃And A₄Is at least 1 selected from the group consisting of pyrrolidine, pyrrole, imidazole, pyrazole, oxazole, thiazole, piperidine, piperazine, pyridine, pyrazine, indole, benzimidazole, quinoline, and isoquinoline.

7. The liquid crystal aligning agent according to any one of claims 1 to 6, wherein Y in the formula (2)₁Is selected from the group consisting of 2-valent organic groups having the following structures of formulae (YD-6) to (YD-21)At least 1.

(in the formula (YD-17), h is an integer of 1-3, and in the formulae (YD-14) and (YD-21), j is an integer of 1-3.)

8. The liquid crystal aligning agent according to 7, wherein Y in the formula (2)₁Is at least 1 selected from the group consisting of 2-valent organic groups having the structures of the above-described formulae (YD-14) and (YD-18).

9. The liquid crystal aligning agent according to any one of claims 1 to 8, wherein the tetracarboxylic dianhydride represented by the formula (1) is 3,3 ', 4, 4' -biphenyltetracarboxylic dianhydride.

10. The liquid crystal aligning agent according to any one of claims 1 to 9, wherein the aliphatic tetracarboxylic dianhydride is bicyclo [3.3.0] octane 2,4,6,8-tetracarboxylic acid 2,4:6,8-dianhydride (bicyclo [3.3.0] octane-2,4,6,8-tetracarboxylic acid-2,4:6, 8-dianhydide).

11. A liquid crystal alignment film obtained by applying the liquid crystal aligning agent of any one of 1 to 10 and firing the same.

12. A liquid crystal display element comprising the liquid crystal alignment film of claim 11.

ADVANTAGEOUS EFFECTS OF INVENTION

The liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention can suppress charge accumulation due to ac drive asymmetry, and is excellent in reworkability.

Detailed Description

The liquid crystal aligning agent of the present invention is characterized by containing: (A-1) at least 1 polymer selected from the group consisting of polyamic acid obtained by using a tetracarboxylic dianhydride component comprising a tetracarboxylic dianhydride represented by the following formula (1) and a diamine component comprising a diamine represented by the following formula (2), and an imidized polymer of the polyamic acid; (A-2) at least 1 polymer selected from the group consisting of polyamic acid obtained by using a tetracarboxylic dianhydride component containing an aliphatic tetracarboxylic dianhydride and a diamine component containing a diamine represented by the following formula (2), and an imidized polymer of the polyamic acid; (B) at least 1 polymer selected from the group consisting of a polyimide precursor, an imidized polymer of the polyimide precursor, and a photosensitive side-chain acrylic polymer exhibiting liquid crystallinity in a specific temperature range; and an organic solvent.

In the formula (1), i is 0 or 1, X is a single bond, an ether bond, a carbonyl group, an ester bond, a phenylene group, a linear alkylene group with 1 to 20 carbon atoms, a branched alkylene group with 2 to 20 carbon atoms, a cyclic alkylene group with 3 to 12 carbon atoms, a sulfonyl group, an amide bond or a group formed by combining the two, wherein the alkylene group with 1 to 20 carbon atoms is optionally interrupted by a bond selected from the ester bond and the ether bond, and the carbon atoms of the phenylene group and the alkylene group are optionally substituted by 1 or more same or different substituents selected from a halogen atom, a cyano group, an alkyl group, a halogenated alkyl group, an alkoxy group and a halogenated alkoxy group.

In the formula (2), Y₁Is a 2-valent organic group having at least 1 structure selected from the group consisting of amino, imino and nitrogen-containing heterocyclic ring, B₁～B₂Each independently represents a hydrogen atom, or an optionally substituted alkyl, alkenyl or alkynyl group having 1 to 10 carbon atoms.

Hereinafter, each of the constituent features will be described in detail.

< component (A-1) and component (A-2) >

The component (A-1) used in the liquid crystal aligning agent of the invention is at least 1 polymer selected from polyamic acid and imide polymer of the polyamic acid, wherein the polyamic acid is obtained by using tetracarboxylic dianhydride component containing tetracarboxylic dianhydride represented by the formula (1) and diamine component containing diamine represented by the formula (2).

The component (a-2) used in the liquid crystal aligning agent of the present invention is at least 1 polymer selected from a polyamic acid obtained by using a tetracarboxylic dianhydride component containing an aliphatic tetracarboxylic dianhydride and a diamine component containing a diamine represented by the formula (2) and an imide polymer of the polyamic acid.

< Tetracarboxylic dianhydride component >

Examples of the tetracarboxylic dianhydride represented by the formula (1) include, but are not limited to, the following compounds.

(wherein q represents an integer of 1 to 20.)

Among the tetracarboxylic dianhydrides represented by the formula (1), the tetracarboxylic dianhydride in which i is 1 in the formula (1), that is, the tetracarboxylic dianhydride having 2 or more benzene rings is preferable from the viewpoint of the effect of improving the reworkability, and among the above specific examples, (1-2) to (1-11) are preferable, and from the viewpoint of containing a biphenyl structure and having a rigid structure, the 3,3 ', 4, 4' -biphenyltetracarboxylic dianhydride represented by the formula (1-5) is particularly preferable.

Specific examples of the aliphatic tetracarboxylic dianhydride used in the present invention include tetracarboxylic dianhydrides represented by the following formula (3).

In the formula, X₁Is any one of the following (X-1) to (X-28).

In the formula (X-1), R₃～R₆Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a phenyl group, and more preferably a hydrogen atom or a methyl group.

Among the above, (X-1) to (X-20) are preferable from the viewpoint of not containing an aromatic moiety, and (X-10) is most preferable from the viewpoint of being particularly difficult to cause thermal imidization.

If the amount of the tetracarboxylic dianhydride represented by the formula (1) in the component (a-1) is too small relative to the total amount of the tetracarboxylic dianhydride component, the effects of the present invention cannot be obtained. Therefore, the amount of the tetracarboxylic dianhydride represented by the formula (1) is preferably 10 to 100 mol%, more preferably 50 to 100 mol%, and still more preferably 80 to 100 mol% based on 1 mol of the total tetracarboxylic dianhydride used for producing the component (a-1).

In the component (A-2), when the amount of the aliphatic acid dianhydride relative to the whole tetracarboxylic acid dianhydride component is too small, the effect of the present invention cannot be obtained. Therefore, the amount of the aliphatic tetracarboxylic dianhydride is preferably 10 to 100 mol%, more preferably 50 to 100 mol%, and still more preferably 80 to 100 mol% based on 1 mol of the total tetracarboxylic dianhydride used for producing the component (a-2).

The tetracarboxylic dianhydride and the aliphatic tetracarboxylic dianhydride represented by the formula (1) may be used alone or in combination of two or more, and in this case, the tetracarboxylic dianhydride and the aliphatic tetracarboxylic dianhydride represented by the formula (1) are preferably used in the above-mentioned preferred amounts in total.

The polyamic acid contained in the liquid crystal aligning agent of the present invention may be a tetracarboxylic dianhydride represented by the following formula (4) in addition to the tetracarboxylic dianhydride and the aliphatic tetracarboxylic dianhydride represented by the formula (1).

In the formula (4), X is a 4-valent organic group, and the structure thereof is not particularly limited. Specific examples thereof include those represented by the following formulae (X-31) to (X-36).

< diamine component >

The diamine component used for the production of the component (A-1) or (A-2) of the present inventionContaining a diamine of the above formula (2). In the formula (2), Y₁Is a 2-valent organic group having at least 1 structure selected from the group consisting of amino groups, imino groups and nitrogen-containing heterocyclic rings, B₁～B₂Each independently represents a hydrogen atom, or an optionally substituted alkyl, alkenyl or alkynyl group having 1 to 10 carbon atoms.

Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a tert-butyl group, a hexyl group, an octyl group, a decyl group, a cyclopentyl group, and a cyclohexyl group. Examples of the alkenyl group include those obtained by replacing 1 or more CH — CH structures present in the alkyl group with a C ═ C structure, and more specifically, vinyl, allyl, 1-propenyl, isopropenyl, 2-butenyl, 1, 3-butadienyl, 2-pentenyl, 2-hexenyl, cyclopropenyl, cyclopentenyl, cyclohexenyl and the like. Examples of the alkynyl group include 1 or more CH groups present in the above-mentioned alkyl group ₂-CH₂Examples of the group obtained by substituting the structure with a C.ident.C structure include ethynyl, 1-propynyl and 2-propynyl.

The alkyl group, alkenyl group and alkynyl group may have a substituent as long as the number of carbon atoms is 1 to 10 as a whole, and may form a ring structure via the substituent. The term "form a ring structure by a substituent" means that substituents are bonded to each other or a part of the parent skeleton to form a ring structure.

Examples of the substituent include a halogen group, a hydroxyl group, a mercapto group, a nitro group, an aryl group, an organooxy group, an organothio group, an organosilyl group, an acyl group, an ester group, a thioester group, a phosphate group, an amide group, an alkyl group, an alkenyl group, and an alkynyl group.

Examples of the halogen group as a substituent include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

Examples of the aryl group as a substituent include a phenyl group. The aryl group is optionally further substituted with other substituents as described above.

As the organic oxy group as a substituent, a structure represented by O-R can be shown. The R groups may be the same or different, and may be, for example, alkyl, alkenyl, alkynyl, aryl, or the like. These R are optionally further substituted with the aforementioned substituents. Specific examples of the alkoxy group include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, and the like.

As the organic thio group as a substituent, a structure represented by-S-R may be shown. Examples of the R include the alkyl group, alkenyl group, alkynyl group, and aryl group. These R are optionally further substituted with the aforementioned substituents. Specific examples of the alkylthio group include a methylthio group, an ethylthio group, a propylthio group, a butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, and an octylthio group.

As the organosilyl group which is a substituent, -Si- (R)₃The structure shown. The R groups may be the same or different, and may be, for example, alkyl, alkenyl, alkynyl, aryl, or the like. These R are optionally further substituted with the aforementioned substituents. Specific examples of the alkylsilyl group include a trimethylsilyl group, a triethylsilyl group, a tripropylsilyl group, a tributylsilyl group, a tripentylsilyl group, a trihexylsilyl group, a pentyldimethylsilyl group, and a hexyldimethylsilyl group.

The acyl group as a substituent may have a structure represented by-C (O) -R. Examples of the R include the alkyl group, the alkenyl group, and the aryl group. These R are optionally further substituted with the aforementioned substituents. Specific examples of the acyl group include formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl, isovaleryl, benzoyl and the like.

The ester group as a substituent may have a structure represented by-C (O) O-R or-OC (O) R. Examples of the R include the alkyl group, alkenyl group, alkynyl group, and aryl group. These R are optionally further substituted with the aforementioned substituents.

The thioester group as a substituent may have a structure represented by-C (S) O-R or-OC (S) -R. Examples of the R include the alkyl group, alkenyl group, alkynyl group, and aryl group. These R are optionally further substituted with the aforementioned substituents.

As the phosphate group as a substituent, there may be mentioned-OP (O) - (OR))₂The structure shown. The R groups may be the same or different, and may be, for example, alkyl, alkenyl, alkynyl, aryl, or the like. These R are optionally further substituted with the aforementioned substituents.

As the amide group as a substituent, there may be mentioned-C (O) NH₂or-C (O) NHR, -NHC (O) R, -C (O) N (R)₂-NRC (O) R. The R groups may be the same or different, and may be, for example, alkyl, alkenyl, alkynyl, aryl, or the like. These R are optionally further substituted with the aforementioned substituents.

Examples of the aryl group as a substituent include the same ones as those of the above-mentioned aryl group. The aryl group is optionally further substituted with other substituents as described above.

Examples of the alkyl group as a substituent include the same ones as those of the above alkyl group. The alkyl group is optionally further substituted with other substituents as described above.

Examples of the alkenyl group as the substituent include the same ones as those described above. The alkenyl group is optionally further substituted with the other substituents described above.

Examples of the alkynyl group as a substituent include the same ones as those described above. The alkynyl group is optionally further substituted with other substituents as described above.

In general, when a bulky structure is introduced, the reactivity of amino groups and the liquid crystal alignment properties may be lowered, and therefore, B is a structure₁And B₂More preferred is a hydrogen atom or an optionally substituted alkyl group having 1 to 5 carbon atoms, and particularly preferred is a hydrogen atom, a methyl group or an ethyl group.

As Y in formula (2)₁The structure of (b) is not particularly limited as long as it has at least 1 structure selected from the group consisting of amino group, imino group and nitrogen-containing heterocycle. Specific examples thereof include 2-valent organic groups having at least 1 structure selected from the group consisting of amino groups, imino groups, and nitrogen-containing heterocycles, represented by the following formulae (YD-1) to (YD-5).

In the formula (YD-1), A₁Is a nitrogen atom-containing heterocycle having 3 to 15 carbon atoms, Z ₁Is a hydrogen atom or an optionally substituted hydrocarbon group having 1 to 20 carbon atoms.

In the formula (YD-2), W₁Is a C1-10 hydrocarbon group, A₂Is a C3-15 organic group having a nitrogen atom-containing heterocycle, or a disubstituted amino group substituted with a C1-6 aliphatic group.

In the formula (YD-3), W₂A C6-15 and a 2-valent organic group having 1-2 benzene rings, W₃Is alkylene or biphenylene having 2 to 5 carbon atoms, Z₂Is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a benzene ring, and a is an integer of 0 to 1.

In the formula (YD-4), A₃Is a nitrogen atom-containing heterocycle having 3 to 15 carbon atoms.

In the formula (YD-5), A₄Is a C3-15 nitrogen atom-containing heterocycle, W₅Is an alkylene group having 2 to 5 carbon atoms.

A as formulae (YD-1), (YD-2), (YD-4) and (YD-5)₁、A₂、A₃And A₄The nitrogen-containing heterocycle of 3 to 15 carbon atoms is not particularly limited as long as it has a known structure. Among them, pyrrolidine, pyrrole, imidazole, pyrazole, oxazole, thiazole, piperidine, piperazine, pyridine, pyrazine, indole, benzimidazole, quinoline, isoquinoline, carbazole are exemplified, and piperazine, piperidine, indole, benzimidazole, imidazole, carbazole and pyridine are more preferable.

Further, as Y in the formula (2)₂Specific examples of (A) include 2-valent organic groups having nitrogen atoms represented by the following formulae (YD-6) to (YD-38), and more preferably formulae (YD-14) to (YD-21), and particularly preferably (YD-14) and (YD-18) in order to suppress charge accumulation due to AC drive.

In the formulas (YD-14) and (YD-21), j is an integer of 0-3. In the formula (YD-17), h is an integer of 1 to 3.

In the formulae (YD-24), (YD-25), (YD-28) and (YD-29), j is an integer of 0 to 3.

The proportion of the diamine represented by formula (2) in the polyamic acid and the imidized polymer of the polyamic acid as component (a-1) or component (a-2) in the present invention is preferably 10 to 100 mol%, more preferably 30 to 100 mol%, and still more preferably 50 to 100 mol% based on 1 mol of the total diamine used in the production of component (a-1) or component (a-2).

In the components (A-1) and (A-2) of the present invention, the diamine represented by the formula (2) in the production of the polyamic acid and the imidized polymer of the polyamic acid may be used alone or in combination of two or more, and in this case, it is preferable to use the total amount of the diamines represented by the formula (2) in the above-mentioned preferable amount. In addition, from the viewpoint of further improving the effect of the present invention, it is preferable to use the same diamine for the component (A-1) and the component (A-2).

In the present invention, it is preferable that the diamines used in producing the polyamic acid and the imidized polymer of the polyamic acid are the same diamines in the components (A-1) and (A-2).

The polyamic acid as the component (A-1) or (A-2) contained in the liquid crystal aligning agent of the present invention may be a diamine represented by the following formula (5) in addition to the diamine represented by the above formula (2). Y in the following formula (5) ₂The organic group is a 2-valent organic group, and the structure thereof is not particularly limited, and 2 or more kinds thereof may be mixed. Specific examples thereof include the following (Y-1) to (Y-49) and (Y-57) to (Y-75).

H₂N-Y₂-NH₂ (5)

The polyamic acid as the component (A-1) or (A-2) contained in the liquid crystal aligning agent of the present invention is not preferable because the effect of the present invention may be impaired when the ratio of the diamine represented by the formula (5) is increased. Therefore, the proportion of the diamine represented by the formula (5) is preferably 0 to 90 mol%, more preferably 0 to 50 mol%, and still more preferably 0 to 20 mol% based on 1 mol of the total diamines.

< method for producing Polyamic acid >

The polyamic acid used in the present invention as a polyimide precursor can be synthesized by the following method.

Specifically, the tetracarboxylic acid dianhydride and the diamine can be synthesized by reacting at-20 to 150 ℃, preferably 0 to 70 ℃ for 30 minutes to 24 hours, preferably 1 to 12 hours in the presence of an organic solvent.

The organic solvent used in the reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, γ -butyrolactone, or the like, and 1 or 2 or more thereof may be used in combination, from the viewpoint of solubility of the monomer and the polymer.

The concentration of the polymer is preferably 1 to 30% by mass, more preferably 5 to 20% by mass, from the viewpoint that the polymer is less likely to precipitate and a high molecular weight product is easily obtained.

The polyamic acid obtained as described above can be recovered by precipitating a polymer by pouring the reaction solution into a poor solvent while sufficiently stirring the reaction solution. Further, the polyamic acid is precipitated several times, washed with a poor solvent, and dried at room temperature or heated to obtain a purified polyamic acid powder. The poor solvent is not particularly limited, and examples thereof include water, methanol, ethanol, 2-propanol, hexane, butyl cellosolve, acetone, toluene, and the like, and water, methanol, ethanol, 2-propanol, and the like are preferable.

< method for producing polyimide >

The polyimide used in the present invention can be produced by imidizing the polyamic acid.

In the case of producing a polyimide from a polyamic acid, chemical imidization by adding a catalyst to a solution of the polyamic acid obtained by reacting a diamine component with a tetracarboxylic dianhydride is simple. Chemical imidization is preferred because the imidization reaction proceeds at a relatively low temperature and the molecular weight of the polymer is less likely to decrease during the imidization.

Chemical imidization can be carried out by stirring a polymer to be imidized in an organic solvent in the presence of a basic catalyst and an acid anhydride. As the organic solvent, a solvent used in the polymerization reaction can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, pyridine is preferable because it has a suitable basicity for advancing the reaction. The acid anhydride may be acetic anhydride, trimellitic anhydride, pyromellitic anhydride, or the like, and among these, acetic anhydride is preferable because purification after completion of the reaction is easy.

The temperature for the imidization is-20 to 140 ℃, preferably 0 to 100 ℃, and the reaction time may be 1 to 100 hours. The amount of the basic catalyst is 0.5 to 30 times by mol, preferably 2 to 20 times by mol, and the amount of the acid anhydride is 1 to 50 times by mol, preferably 3 to 30 times by mol, based on the amount of the polyamic acid group. The imidization rate of the obtained polymer can be controlled by adjusting the amount of the catalyst, the temperature and the reaction time.

Since the added catalyst and the like remain in the solution after the imidization reaction of the polyamic acid, it is preferable to recover the obtained imidized polymer by the following means and redissolve it with an organic solvent to prepare the liquid crystal aligning agent of the present invention.

The solution of polyimide obtained as described above can be injected into a poor solvent with sufficient stirring to precipitate a polymer. The polymer powder is obtained by precipitation several times, washing with a poor solvent, and drying at room temperature or by heating.

The poor solvent is not particularly limited, and examples thereof include methanol, 2-propanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, and benzene, and methanol, ethanol, 2-propanol, and acetone are preferable.

The content ratio of the component (a-1) to the component (a-2) produced in this way is a content ratio of the tetracarboxylic dianhydride represented by the above formula (1) to the aliphatic tetracarboxylic dianhydride, which is 10: 90-90: 10, preferably 20: 80-80: 20. more preferably 40: 60-60: 40, particularly preferably 46: 54-54: 46, most preferably substantially equal amounts.

< ingredient (B) >

The component (B) contained in the liquid crystal aligning agent of the present invention is at least 1 polymer selected from the group consisting of a polyimide precursor, an imidized polymer of the polyimide precursor, and a photosensitive side chain type acrylic polymer which exhibits liquid crystallinity in a specific temperature range.

< polyimide precursor >

The polyimide precursor is a polyimide precursor having a structural unit represented by formula (11) below.

In formula (11), X₁₁Each independently is a 4-valent organic radical, Y₁₁Each independently is a 2-valent organic group. R₁₁Is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, A₁₁～A₁₂Each independently represents a hydrogen atom, or an optionally substituted alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms orAn alkynyl group having 2 to 10 carbon atoms.

As R₁₁Specific examples of the alkyl group include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, and n-pentyl groups. R is R from the viewpoint of ease of imidation by heating₁₁Preferably a hydrogen atom or a methyl group.

In formula (11), X₁₁The organic group having a valence of 4 derived from a tetracarboxylic acid derivative, and the structure thereof is not particularly limited. In the polyimide precursor, X₁₁More than 2 species may be present in combination. If X is to be shown₁₁Specific examples of (A) include the following formulae (X-1) to (X-44).

R in the above formula (X-1)₈～R₁₁Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group or a phenyl group. R₈～R₁₁In the case of a bulky structure, since there is a possibility that the liquid crystal alignment property is lowered, a hydrogen atom, a methyl group, or an ethyl group is more preferable, and a hydrogen atom or a methyl group is particularly preferable.

In the formula (11), X is X from the viewpoint of availability of the monomer₁₁Preferably contains a structure selected from (X-1) to (X-14).

The preferable ratio of the structures selected from the above (X-1) to (X-14) is X₁₁20 mol% or more, more preferably 60 mol% or more, and still more preferably 80 mol% or more of the whole.

In the formula (11), A₁₁And A₁₂Each independently represents a hydrogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, an optionally substituted alkenyl group having 2 to 10 carbon atoms, or an optionally substituted alkynyl group having 2 to 10 carbon atoms.

These A' s₁₁And A₁₂Specific examples and preferred examples of (A) and (A-2) component (B)₁And B₂The same is true.

In the formula (11), Y₁₁The diamine-derived organic group has a valence of 2, and the structure thereof is not particularly limited. If Y is to be shown₁₁Specific examples of the structure of (A) include the above-mentioned (Y-1) to (Y-49) and (Y-57) to (Y-75) and (YD-6) to (YD-38) described in the above-mentioned item of component (A). In addition, the following (Y-76) to (Y-97) and (YD-39) to (YD-52) can be mentioned.

(in the formula (YD-50), m and n are integers of 1-11 and m + n is an integer of 2-12.)

As Y₁₁The structure of (3) is more preferably at least 1 selected from the structures represented by the following formulae (15) and (16) from the viewpoint of the liquid crystal alignment property and pretilt angle of the obtained liquid crystal alignment film.

In the formula (15), R₁₂Is a single bond or a C1-30 2-valent organic group, R₁₃Is a hydrogen atom, a halogen atom or a 1-valent organic group having 1 to 30 carbon atoms, a is an integer of 1 to 4, and when a is 2 or more, R is₁₂、R₁₃R in the formula (16) may be the same as or different from each other₁₄Is a single bond, -O-, -S-, -NR₁₅-, an amide bond, an ester bond, a urea bond, or a C1-40 2-valent organic group, R₁₅Is a hydrogen atom or a methyl group.

Specific examples of the formula (15) and the formula (16) include the following structures.

The structure having high linearity can improve the alignment of liquid crystal when formed into a liquid crystal alignment film, and thus is used as Y₁₁Further, Y-7, Y-21, Y-22, Y-23, Y-25, Y-43, Y-44, Y-45, Y-46, Y-48, Y-63, Y-71, Y-72, Y-73, Y-74, and Y-75 are preferable. The ratio of the above-mentioned structure which can improve the liquid crystal alignment property is preferably Y₁₁20 mol% or more, more preferably 60 mol% or more, and still more preferably 80 mol% or more of the whole.

When it is desired to increase the pretilt angle of the liquid crystal when the liquid crystal alignment film is formed, it is preferable that Y is the pretilt angle₁₁The side chain of (1) has a long-chain alkyl group, an aromatic ring, an alicyclic ring, a steroid skeleton, or a combination thereof. As such Y ₁₁Y-76, Y-77, Y-78, Y-79, Y-80, Y-81, Y-82, Y-83, Y-84, Y-85, Y-86, Y-87, Y-88, Y-89, Y-90, Y-91, Y-92, Y-93, Y-94, Y-95, Y-96, Y-97 are preferred. The ratio of the above structure when it is desired to increase the pretilt angle is preferably Y₁₁1 to 30 mol%, more preferably 1 to 20 mol% of the whole.

In the case of using a polyimide (precursor) having a photo-alignment side chain as the polymer of the component (B), a polyimide (precursor) having a photoreactive side chain described below is preferably used.

-R¹⁶-R¹⁷-R¹⁸-R¹⁹ (b)

(R¹⁶represents-CH₂-、-O-、-COO-、-OCO-、-NHCO-、-CONH-、-NH-、-CH₂O-、-N(CH₃)-、-CON(CH₃)-、-N(CH₃) Any one of CO-, R¹⁷Represents a cyclic, unsubstituted or fluorine atom-substituted alkylene group having 1 to 20 carbon atoms, wherein the alkylene group optionally has-CH₂Optionally with-CF₂-or-C ═ C-substitution, optionally in the case where any of the groups listed below are not adjacent to one another, with these groups; -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, carbocycle, heterocycle. R¹⁸represents-CH₂-、-O-、-COO-、-OCO-、-NHCO-、-NH-、-N(CH₃)-、-CON(CH₃)-、-N(CH₃) CO-, carbocyclic or heterocyclic, R¹⁹Represents vinylphenyl, -CR²⁰＝CH₂radical-CR²⁰(OH)-CH₃A group, a carbocyclic ring, a heterocyclic ring or a structure represented by a formula selected from the group consisting of R²⁰Represents a hydrogen atom or a methyl group optionally substituted by a fluorine atom. )

In the case of producing such a polyimide precursor, it is convenient to use a diamine substituted with a side chain represented by the above formula (b) as the diamine.

In addition, a polyimide precursor having a main chain with a photo-alignment group may be used. In this case, it is convenient to use a diamine having a bond containing a photo-alignment group between an amine and an amine as shown in the following formula (21).

(in formula (21), X²¹Is a single bond or C1-5 alkylene, X²²is-OCO-CH-or-CH-COO-, X²³Is a single bond, C1-10 alkylene or 2-valent benzene ring, X²⁴Is a single bond, -OCO-CH ═ CH-or-CH ═ CH-COO-, X²⁵Is a single bond or C1-5 alkylene. Wherein, the number of cinnamoyl groups is 1 or more. )

Examples of the diamine represented by the formula (21) include the following diamines.

(wherein X is independently a single bond or a bonding group selected from the group consisting of ether (-O-), ester (-COO-or-OCO-) and amide (-CONH-or-NHCO-), Y is independently a single bond or an alkylene group having 1 to 5 carbon atoms, and Z is independently an alkylene group or phenylene group having 1 to 10 carbon atoms, the bonding position of the amino group to the benzene ring or the position of the bonding group to the central benzene ring are not particularly limited.)

Specific examples of the diamine represented by the formula (21) include the following diamines.

The liquid crystal alignment film formed using such a liquid crystal aligning agent containing a polyimide precursor such as a polyamic acid or polyamic acid ester, which is obtained by using the diamine represented by the formula (21) as a raw material, and a polyimide or polyamide is a film in which a change in liquid crystal alignment performance, for example, a change in alignment orientation of liquid crystal, due to AC (alternating current) driving is reduced. Therefore, in the liquid crystal display element having the liquid crystal alignment film, since the liquid crystal alignment performance of the liquid crystal alignment film under AC driving is stable, the liquid crystal display element has an effect that image sticking is less likely to occur due to AC driving, that is, image sticking characteristics by AC driving are very good. Further, the liquid crystal alignment film formed using the diamine represented by the above formula (21) can be a film which is excellent in liquid crystal alignment performance itself and substantially free from alignment defects.

The polyimide precursor used in the present invention is obtained by reacting a diamine component with a tetracarboxylic acid derivative, and examples thereof include polyamic acids and polyamic acid esters.

< preparation of Polyamic acid, polyimide precursor >

The method for producing the polyamic acid according to the items of the components (A-1) and (A-2).

< production of polyimide precursor-polyamic acid ester >

The polyamic acid ester as a polyimide precursor used in the present invention can be produced by the production method of (1), (2) or (3) shown below.

(1) When produced from polyamic acid

The polyamic acid ester can be produced by esterifying the polyamic acid produced as described above. Specifically, the polyamic acid can be produced by reacting a polyamic acid with an esterifying agent in the presence of an organic solvent at-20 to 150 ℃, preferably 0 to 50 ℃, for 30 minutes to 24 hours, preferably 1 to 4 hours.

As the esterification agent, preferred can be purified and easily removed substances, can be cited, N-two methyl formamide two methyl acetal, N-two methyl formamide two ethyl acetal, N-two methyl formamide two propyl acetal, N-two methyl formamide two neopentyl butyl acetal, N-two methyl formamide two tert butyl acetal, 1-methyl-3-p-three phenyl nitrogen alkene, 1-ethyl-3-p-three phenyl nitrogen alkene, 1-propyl-3-p-three phenyl nitrogen alkene, 4- (4, 6-two methoxy-1, 3, 5-three triazine-2-yl) -4-methyl morpholine hydrochloride. The amount of the esterifying agent added is preferably 2 to 6 molar equivalents based on 1 mole of the repeating unit of the polyamic acid.

Examples of the organic solvent include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ -butyrolactone, N-dimethylformamide, N-dimethylacetamide, dimethylsulfoxide, and 1, 3-dimethyl-imidazolidinone. When the polyimide precursor has high solubility in the solvent, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or a solvent represented by the following formulae [ D-1] to [ D-3] may be used.

These solvents may be used alone or in combination. Further, even if the solvent is a solvent which does not dissolve the polyimide precursor, the solvent may be mixed with the polyimide precursor and used as long as the produced polyimide precursor is not precipitated. Further, the water content in the solvent is a cause of inhibiting the polymerization reaction and even hydrolyzing the polyimide precursor produced, and therefore, the solvent is preferably used after dehydration and drying.

The solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone or γ -butyrolactone, and 1 or 2 or more thereof may be used in combination, from the viewpoint of solubility of the polymer. The concentration during production is preferably 1 to 30% by mass, more preferably 5 to 20% by mass, from the viewpoint that precipitation of a polymer is not likely to occur and a high molecular weight material is easily obtained.

(2) When produced by the reaction of a tetracarboxylic acid diester diacid chloride with a diamine

The polyamic acid ester can be produced from a tetracarboxylic acid diester diacid chloride and a diamine.

Specifically, the tetracarboxylic acid diester can be produced by reacting a tetracarboxylic acid diester diacid chloride with a diamine in the presence of a base and an organic solvent at-20 to 150 ℃, preferably 0 to 50 ℃, for 30 minutes to 24 hours, preferably 1 to 4 hours.

Pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used as the base, and pyridine is preferable in order to allow the reaction to proceed smoothly. The amount of the base to be added is preferably 2 to 4 times by mol based on the tetracarboxylic acid diester diacid chloride, from the viewpoint of ease of removal and availability of a high molecular weight product.

The solvent used in the above reaction is preferably N-methyl-2-pyrrolidone or γ -butyrolactone, and 1 or 2 or more thereof may be used in combination, from the viewpoint of solubility of the monomer and the polymer. The polymer concentration during production is preferably 1 to 30% by mass, more preferably 5 to 20% by mass, from the viewpoint that precipitation of the polymer is not likely to occur and a high molecular weight product is easily obtained. In order to prevent hydrolysis of the tetracarboxylic acid diester diacid chloride, the solvent used in the production of the polyamic acid ester is preferably dehydrated as much as possible, and is preferably kept in a nitrogen atmosphere to prevent the mixing of the outside air.

(3) When produced from a tetracarboxylic acid diester and a diamine

The polyamic acid ester can be produced by polycondensation of a tetracarboxylic acid diester and a diamine.

Specifically, the tetracarboxylic acid diester can be produced by reacting a tetracarboxylic acid diester with a diamine in the presence of a condensing agent, a base and an organic solvent at 0 to 150 ℃, preferably 0 to 100 ℃, for 30 minutes to 24 hours, preferably 3 to 15 hours.

As the condensing agent, triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, N, N ' -carbonyldiimidazole, dimethoxy-1, 3, 5-triazinylmethyl morpholinium, O- (benzotriazol-1-yl) -N, N, N ', N ' -tetramethyluronium tetrafluoroborate, O- (benzotriazol-1-yl) -N, N, N ', N ' -tetramethyluronium hexafluorophosphate, (2, 3-dihydro-2-thio-3-benzoxazolyl) diphenyl phosphonate, and the like can be used. The amount of the condensing agent to be added is preferably 2 to 3 times by mol based on the tetracarboxylic acid diester.

As the base, tertiary amines such as pyridine and triethylamine can be used. The amount of the base to be added is preferably 2 to 4 times by mol based on the diamine component, from the viewpoint of easy removal and easy availability of a high molecular weight material.

In addition, in the above reaction, the reaction proceeds efficiently by adding a lewis acid as an additive. The lewis acid is preferably a lithium halide such as lithium chloride or lithium bromide. The amount of the Lewis acid added is preferably 0 to 1.0 mol per mol of the diamine component.

Among the above-mentioned 3 methods for producing polyamic acid esters, the above-mentioned (1) or (2) method is particularly preferred in order to obtain a polyamic acid ester having a high molecular weight.

The solution of the polyamic acid ester obtained as described above can be poured into a poor solvent while sufficiently stirring, thereby precipitating a polymer. The polyamic acid ester powder can be obtained by precipitation several times, washing with a poor solvent, and drying at room temperature or heating. The poor solvent is not particularly limited, and examples thereof include water, methanol, ethanol, hexane, butyl cellosolve, acetone, and toluene.

< polyimide >

The polyimide used in the present invention can be produced by imidizing the polyamic acid ester or polyamic acid. The method for producing a polyimide as described in the section for the component (A-1) and the component (A-2).

< photosensitive side-chain acrylic Polymer exhibiting liquid Crystal Properties in a specific temperature Range >

(B) One form of the component (A) is a photosensitive side chain type acrylic polymer which exhibits liquid crystallinity in a specific temperature range.

The side chain type acrylic polymer may be reacted with light having a wavelength of 250 to 400nm and exhibit liquid crystallinity at a temperature of 100 to 300 ℃.

The side chain type acrylic polymer preferably has a photosensitive side chain which reacts with light having a wavelength in the range of 250nm to 400 nm.

The side chain type acrylic polymer preferably has a mesogen group exhibiting liquid crystallinity in a temperature range of 100 to 300 ℃.

The side chain type acrylic polymer has a photosensitive side chain bonded to a main chain, and is capable of undergoing a crosslinking reaction, an isomerization reaction, or a photo-fries rearrangement in response to light. The side chain structure having photosensitivity is not particularly limited, and a structure in which a crosslinking reaction or a photo-fries rearrangement occurs in response to light is desirable, and a structure in which a crosslinking reaction occurs is more desirable. In this case, the achieved orientation controlling ability can be stably maintained for a long period of time even if exposed to external stress such as heat. The structure of the photosensitive side chain type acrylic polymer film capable of exhibiting liquid crystallinity is not particularly limited as long as such characteristics are satisfied, and a mesogen component having rigidity in the side chain structure is preferable. In this case, when the side chain type acrylic polymer is formed into a liquid crystal alignment film, stable liquid crystal alignment can be obtained.

The structure of the acrylic polymer can be made, for example, as follows: a main chain and a side chain bonded thereto, the side chain having a structure in which a mesogen component such as biphenyl, terphenyl, phenylcyclohexyl, phenylbenzoate, or azophenyl group and a photosensitive group which is bonded to a distal end portion and which undergoes a crosslinking reaction or an isomerization reaction in response to light are bonded; has a main chain and a side chain bonded thereto, the side chain having a structure of a benzoate group which is a mesogen component and also causes a photo-Fries rearrangement reaction.

More specific examples of the structure of the photosensitive side chain type acrylic polymer exhibiting liquid crystallinity in a specific temperature range preferably include a structure having a main chain composed of at least 1 kind selected from the group consisting of hydrocarbon, (meth) acrylate, itaconate, fumarate, maleate, α -methylene- γ -butyrolactone, styrene, vinyl, maleimide, norbornene and other radical polymerizable groups, and a side chain composed of at least 1 kind selected from the group consisting of formulae (31) to (35).

In the formula, Ar₁Ar represents a 2-valent substituent obtained by removing 2 hydrogen atoms from a benzene ring, a naphthalene ring, a pyrrole ring, a furan ring, a thiophene ring, or a pyridine ring₂And Ar₃Each independently represents a 2-valent substituent obtained by removing 2 hydrogen atoms from a benzene ring, a naphthalene ring, a pyrrole ring, a furan ring, a thiophene ring and a pyridine ring, and q¹And q is²One is 1 and the other is 0, Ar₄And Ar₅Each independently represents a 2-valent substituent obtained by removing 2 hydrogen atoms from a benzene ring, a naphthalene ring, a pyrrole ring, a furan ring, a thiophene ring and a pyridine ring, and Y₁-Y₂Denotes CH ═ CH, CH ═ N, N ═ CH, or C ≡ C, S₁～S₃Each independently represents a single bond, a linear or branched alkylene group having 1 to 18 carbon atoms, a cycloalkylene group having 5 to 8 carbon atoms, a phenylene group or a biphenylene group; or represents 1 or 2 or more bonds selected from single bond, ether bond, ester bond, amide bond, urea bond, urethane bond, ammonia bond, carbonyl group or their combination; or a structure in which 2 or more and 10 or less sites selected from the group consisting of a linear or branched alkylene group having 1 to 18 carbon atoms, a cycloalkylene group having 5 to 8 carbon atoms, a phenylene group, a biphenylene group, and a combination thereof are bonded through the 1 or 2 or more bonds, or a structure in which a plurality of the substituents are connected through the bond,

R³¹Represents a hydrogen atom, a hydroxyl group, a mercapto group, an amino group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylamino group having 1 to 8 carbon atoms or a dialkylamino group having 2 to 16 carbon atoms, and the benzene ring and/or the naphthalene ring is optionally substituted with 1 or more substituents which may be the same or different, selected from a halogen atom, a cyano group, a nitro group, a carboxyl group and an alkoxycarbonyl group having 2 to 11 carbon atoms. In this case, the alkyl group having 1 to 10 carbon atoms may be linear, branched or cyclic, may have a structure obtained by combining these, and may be optionally substituted with a halogen atom.

The photosensitive side chain acrylic polymer which exhibits liquid crystallinity in a specific temperature range as the component (B) of the present application may contain a liquid crystalline side chain.

The mesogenic group of the liquid crystalline side chain may be a group having a single mesogenic structure such as biphenyl or phenyl benzoate, or may be a group having a mesogenic structure in which side chains are hydrogen-bonded to each other such as benzoic acid. The following structure is preferred as the mesogen group of the side chain.

[ method for producing photosensitive side-chain type Polymer ]

The photosensitive side chain type acrylic polymer exhibiting liquid crystallinity in a specific temperature range can be obtained by polymerizing a photoreactive side chain monomer having the photosensitive side chain and a liquid crystalline side chain monomer.

[ photoreactive side chain monomer ]

The photoreactive side chain monomer is a monomer that can form a polymer having a photosensitive side chain at a side chain site of the polymer when forming the polymer.

The photoreactive group in the side chain is preferably a structure represented by the above formulas (31) to (35).

More specific examples of the photoreactive side chain monomer include those having a polymerizable group of at least 1 kind selected from the group consisting of hydrocarbon, (meth) acrylate, itaconate, fumarate, maleate, α -methylene- γ -butyrolactone, styrene, vinyl, maleimide, norbornene and other radical polymerizable groups, and a photosensitive side chain formed of at least 1 kind of the above-mentioned formulae (31) to (35).

[ liquid Crystal side chain monomer ]

The liquid crystalline side chain monomer is a monomer in which a polymer derived from the monomer exhibits liquid crystallinity and the polymer can form a mesogenic group at a side chain position.

More specific examples of the liquid crystalline side chain monomer are preferably those having a structure having a polymerizable group composed of at least 1 selected from the group consisting of radical polymerizable groups such as hydrocarbons, (meth) acrylates, itaconates, fumarates, maleates, α -methylene- γ -butyrolactones, styrenes, vinyls, maleimides, and norbornenes, and a side chain having at least 1 of the "mesogenic groups of the liquid crystalline side chain".

The side chain type acrylic polymer as one form of the component (B) can be obtained by polymerization reaction of the above photoreactive side chain monomer exhibiting liquid crystallinity. The side chain monomer can be obtained by copolymerization of a photoreactive side chain monomer that does not exhibit liquid crystallinity and a liquid crystalline side chain monomer, or copolymerization of a photoreactive side chain monomer that exhibits liquid crystallinity and a liquid crystalline side chain monomer. Further, the monomer may be copolymerized with other monomers within a range not impairing the expression ability of liquid crystallinity.

Examples of the other monomers include industrially available monomers capable of radical polymerization.

Specific examples of the other monomer include unsaturated carboxylic acids, acrylate compounds, methacrylate compounds, maleimide compounds, acrylonitrile, maleic anhydride, styrene compounds, vinyl compounds, and the like.

Specific examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, itaconic acid, maleic acid, and fumaric acid.

Examples of the acrylate compound include methyl acrylate, ethyl acrylate, isopropyl acrylate, benzyl acrylate, naphthyl acrylate, anthryl methyl acrylate, phenyl acrylate, 2,2, 2-trifluoroethyl acrylate, t-butyl acrylate, cyclohexyl acrylate, isobornyl acrylate, 2-methoxyethyl acrylate, methoxytriethylene glycol acrylate, 2-ethoxyethyl acrylate, tetrahydrofurfuryl acrylate, 3-methoxybutyl acrylate, 2-methyl-2-adamantyl acrylate, 2-propyl-2-adamantyl acrylate, 8-methyl-8-tricyclodecanyl acrylate, and 8-ethyl-8-tricyclodecanyl acrylate.

Examples of the methacrylate compound include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, benzyl methacrylate, naphthyl methacrylate, anthryl methyl methacrylate, phenyl methacrylate, 2,2, 2-trifluoroethyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, 2-methoxyethyl methacrylate, methoxytriethylene glycol methacrylate, 2-ethoxyethyl methacrylate, tetrahydrofurfuryl methacrylate, 3-methoxybutyl methacrylate, 2-methyl-2-adamantyl methacrylate, 2-propyl-2-adamantyl methacrylate, and mixtures thereof, 8-methyl-8-tricyclodecyl methacrylate, and 8-ethyl-8-tricyclodecyl methacrylate. (meth) acrylate compounds having a cyclic ether group such as glycidyl (meth) acrylate, (3-methyl-3-oxetanyl) methyl (meth) acrylate and (3-ethyl-3-oxetanyl) methyl (meth) acrylate can also be used.

Examples of the vinyl compound include vinyl ether, methyl vinyl ether, benzyl vinyl ether, 2-hydroxyethyl vinyl ether, phenyl vinyl ether, and propyl vinyl ether.

Examples of the styrene compound include styrene, methylstyrene, chlorostyrene, bromostyrene, and the like.

Examples of the maleimide compound include maleimide, N-methylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide.

The method for producing the side chain polymer of the present embodiment is not particularly limited, and an industrially applicable general method can be used. Specifically, the polymer can be produced by cationic polymerization, radical polymerization, or anionic polymerization using a vinyl group of a liquid crystalline side chain monomer or a photoreactive side chain monomer. Among these, radical polymerization is particularly preferable from the viewpoint of ease of reaction control and the like.

As the polymerization initiator for radical polymerization, a known radical polymerization initiator such as AIBN (azobisisobutyronitrile), a known compound such as a reversible addition-fragmentation chain transfer (RAFT) polymerization reagent, or the like can be used.

The radical polymerization method is not particularly limited, and emulsion polymerization, suspension polymerization, dispersion polymerization, precipitation polymerization, bulk polymerization, solution polymerization, and the like can be used.

The organic solvent used for the polymerization reaction of the photosensitive side chain type acrylic polymer exhibiting liquid crystallinity in a specific temperature range is not particularly limited as long as it is an organic solvent that dissolves the resulting polymer. Specific examples thereof are listed below.

There may be mentioned: n, N-dimethylformamide, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, tetramethylurea, pyridine, dimethyl sulfone, hexamethylsulfoxide, gamma-butyrolactone, isopropanol, methoxymethylpentanol, dipentene, ethylpentyl ketone, methylnonyl ketone, methylethyl ketone, methylisoamyl ketone, methylisopropyl ketone, methylcellosolve, ethylcellosolve, methylcellosolve acetate, ethylcellosolve acetate, butylcarbitol, ethylcarbitol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol monomethyl ether, propylene glycol, Diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, dioxane, n-hexane, n-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl propionate, ethyl propionate, and ethyl propionate, ethyl, Methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionate, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, diglyme, 4-hydroxy-4-methyl-2-pentanone, 3-methoxy-N, N-dimethylpropionamide, 3-ethoxy-N, N-dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide, and the like.

These organic solvents may be used alone or in combination. Further, even if the solvent is not capable of dissolving the produced polymer, the solvent may be mixed with the organic solvent and used as long as the produced polymer is not precipitated.

In addition, in radical polymerization, oxygen in an organic solvent may cause inhibition of the polymerization reaction, and therefore, it is preferable to use the organic solvent after degassing as much as possible.

The polymerization temperature in the radical polymerization may be any temperature of 30 to 150 ℃, and preferably in the range of 50 to 100 ℃. The reaction may be carried out at any concentration, and when the concentration is too low, it is difficult to obtain a polymer having a high molecular weight, and when the concentration is too high, the viscosity of the reaction solution becomes too high and uniform stirring is difficult, and therefore the monomer concentration is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction may be carried out at a high concentration at the initial stage of the reaction, and then an organic solvent may be added.

In the radical polymerization reaction, the ratio of the radical polymerization initiator to the monomer is preferably 0.1 to 10 mol% because the molecular weight of the resulting polymer becomes smaller when the ratio of the radical polymerization initiator to the monomer is large and the molecular weight of the resulting polymer becomes larger when the ratio is small. In addition, various monomer components, solvents, initiators, and the like may be added during the polymerization.

[ recovery of photosensitive side-chain acrylic Polymer exhibiting liquid crystallinity in a specific temperature range ]

When the polymer produced is recovered from the reaction solution of the photosensitive side chain type polymer capable of exhibiting liquid crystallinity obtained by the above reaction, the reaction solution may be charged into a poor solvent to precipitate the polymer. Examples of the poor solvent used for precipitation include methanol, acetone, hexane, heptane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, diethyl ether, methyl ethyl ether, and water. The polymer precipitated by being charged into the poor solvent may be recovered by filtration, and then dried at normal temperature or under reduced pressure or dried by heating. Further, when the operation of re-dissolving the polymer recovered by precipitation in the organic solvent and re-precipitating and recovering is repeated 2 to 10 times, impurities in the polymer can be reduced. Examples of the poor solvent in this case include alcohols, ketones, hydrocarbons and the like, and when 3 or more kinds of poor solvents selected from these are used, the purification efficiency is further improved, which is preferable.

The weight average molecular weight of the photosensitive side chain acrylic polymer, which is one form of the component (B) and exhibits liquid crystallinity in a specific temperature range, is preferably 2000 to 1000000, more preferably 5000 to 100000, as measured by GPC (Gel Permeation Chromatography) in consideration of the strength of the obtained coating film, workability in forming the coating film, and uniformity of the coating film.

The content of the component (A-1), the component (A-2) and the component (B) in the liquid crystal aligning agent of the present invention is such that the mass ratio of the total amount of the component (A-1) and the component (A-2) to the component (B) is 5: 95-95: 5. more preferably 10: 90-90: 10.

the imidization rates of the component (A-1), the component (A-2) and the component (B) in the liquid crystal aligning agent of the present invention can be arbitrarily adjusted according to the application or purpose, and the imidization rates of the specific polymer component (A-1) and the component (A-2) are preferably 0 to 55%, more preferably 0 to 20%, from the viewpoints of solubility and charge storage characteristics. From the viewpoints of the alignment property, alignment controllability, and voltage holding ratio of the liquid crystal, the imidization ratio of the specific polymer (B) is preferably high, and is preferably 40% to 95%, and more preferably 55% to 90%.

< liquid Crystal alignment agent >

The liquid crystal aligning agent used in the present invention has a solution form in which a polymer component is dissolved in an organic solvent. The molecular weight of the polymer is preferably 2000 to 500000, more preferably 5000 to 300000, and further preferably 10000 to 100000 in terms of weight average molecular weight. The number average molecular weight is preferably 1000 to 250000, more preferably 2500 to 150000, and further preferably 5000 to 50000.

The polymer concentration of the liquid crystal aligning agent used in the present invention may be appropriately changed depending on the setting of the thickness of a coating film to be formed, and is preferably 1 mass% or more from the viewpoint of forming a uniform and defect-free coating film, and is preferably 10 mass% or less from the viewpoint of the storage stability of a solution. The concentration of the polymer is particularly preferably 2 to 8 mass%.

The organic solvent contained in the liquid crystal aligning agent used in the present invention is not particularly limited as long as it is a solvent that uniformly dissolves the polymer component. Specific examples thereof include N, N-dimethylformamide, N-diethylformamide, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-vinyl-2-pyrrolidone, dimethyl sulfoxide, dimethyl sulfone, γ -butyrolactone, 1, 3-dimethylimidazolidinone, and 3-methoxy-N, N-dimethylpropionamide. These may be used in 1 kind or in combination of 2 or more kinds. The solvent which cannot uniformly dissolve the polymer component alone may be mixed with the organic solvent as long as the polymer does not precipitate.

In addition, a mixed solvent in which a solvent that improves coatability or surface smoothness of a coating film at the time of coating the liquid crystal aligning agent is used in combination with the above-mentioned solvent is generally used as the organic solvent contained in the liquid crystal aligning agent, and such a mixed solvent is also preferably used in the liquid crystal aligning agent of the present invention. Specific examples of the organic solvent used in combination are given below, but the organic solvent is not limited to these examples.

Examples thereof include ethanol, isopropanol, 1-butanol, 2-butanol, isobutanol, t-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, isopentanol, t-pentanol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-ethyl-1-hexanol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 2, 6-dimethyl-4-heptanol, isobutanol, 2-methyl-1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-ethyl-1-pentanol, 3-methyl-1-butanol, 2-methyl-1-heptanol, 2-6-dimethyl-4-heptanol, 2-butanol, 2-methyl-hexanol, 2-methyl-2-methyl-1-2-pentanol, 2-methyl-2-hexanol, 2-methyl-2-methyl-1-pentanol, 2-methyl-2-methyl-ethyl-1-hexanol, 2-methyl-butanol, 2-methyl-ethyl-butanol, 2-methyl-2-butanol, 2-ethyl-pentanol, 2-methyl-ethyl-2, 2-methyl-2-ethyl-methyl-2-hexanol, 2-methyl-2, 2-ethyl-2, 2-methyl-2, 2-methyl-ethyl-pentanol, 2-methyl-ethyl-1-2, 2-ethyl-2, 2-ethyl-2-pentanol, 2-methyl-2, 2-methyl-ethyl-2-ethyl-2, 2-ethyl-methyl-ethyl-2, 2-methyl-2, 2-methyl-2-methyl-ethyl-methyl-ethyl-methyl-pentanol, 2-hexanol, 2-methyl-2, 2-methyl-ethyl alcohol, 2-ethyl alcohol, 2, 1, 2-ethanediol, 1, 2-propanediol, 1, 3-propanediol, 1, 2-butanediol, 1, 3-butanediol, 1, 4-butanediol, 2, 3-butanediol, 1, 5-pentanediol, 2-methyl-2, 4-pentanediol, 2-ethyl-1, 3-hexanediol, diisopropyl ether, dipropyl ether, dibutyl ether, dihexyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1, 2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 2-pentanone, 3-pentanone, 2-hexanone, 2-heptanone, 4-heptanone, 2, 6-dimethyl-4-heptanone, 4, 6-dimethyl-2-heptanone, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, 2- (methoxymethoxy) ethanol, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, 2- (hexyloxy) ethanol, furfuryl alcohol, diethylene glycol, propylene glycol, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, propylene glycol monobutyl ether, 1- (butoxyethoxy) propanol, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, propylene glycol methyl ether, propylene glycol methyl ether, and mixtures thereof, Tripropylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monoacetate, ethylene glycol diacetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2- (2-ethoxyethoxy) ethyl acetate, diethylene glycol acetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, methyl acetate, ethyl 3-ethoxypropionate, ethyl acetate, 3-ethoxypropionate, propyl acetate, ethyl, Butyl 3-methoxypropionate, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, and solvents represented by the following formulae [ D-1] to [ D-3 ].

Formula [ D-1 ]]In (D)¹Represents an alkyl group having 1 to 3 carbon atoms of the formula [ D-2 ]]In (D)²Represents an alkyl group having 1 to 3 carbon atoms, formula [ D-3 ]]In (D)³Represents an alkyl group having 1 to 4 carbon atoms.

Among them, preferable combinations of solvents include: n-methyl-2-pyrrolidone, gamma-butyrolactone, and ethylene glycol monobutyl ether; n-methyl-2-pyrrolidone, gamma-butyrolactone and propylene glycol monobutyl ether; n-ethyl-2-pyrrolidone and propylene glycol monobutyl ether; n-methyl-2-pyrrolidone, γ -butyrolactone, 4-hydroxy-4-methyl-2-pentanone, and diethylene glycol diethyl ether; n-methyl-2-pyrrolidone, gamma-butyrolactone, propylene glycol monobutyl ether, and 2, 6-dimethyl-4-heptanone; n-methyl-2-pyrrolidone, gamma-butyrolactone, propylene glycol monobutyl ether, and diisopropyl ether; n-methyl-2-pyrrolidone, gamma-butyrolactone, propylene glycol monobutyl ether, and 2, 6-dimethyl-4-heptanol; n-methyl-2-pyrrolidone, gamma-butyrolactone and dipropylene glycol dimethyl ether. The kind and content of such a solvent are appropriately selected depending on the coating apparatus, coating conditions, coating environment, and the like of the liquid crystal aligning agent.

In addition, the following additives may be added to the liquid crystal aligning agent of the present invention in order to improve the mechanical strength of the film.

The additive is preferably 0.1 to 30 parts by mass per 100 parts by mass of the polymer component contained in the liquid crystal aligning agent. When the amount is less than 0.1 part by mass, no effect is expected, and when the amount is more than 30 parts by mass, the liquid crystal alignment property is lowered, and therefore, the amount is more preferably 0.5 to 20 parts by mass.

In addition to the above, the liquid crystal aligning agent of the present invention may be added within a range not to impair the effects of the present invention: a polymer other than a polymer; a dielectric or conductive substance for changing electric characteristics such as a dielectric constant and conductivity of the liquid crystal alignment film; a silane coupling agent for improving the adhesion between the liquid crystal alignment film and the substrate; a crosslinkable compound for improving film hardness and density when the liquid crystal alignment film is produced; and an imidization accelerator for efficiently promoting imidization of polyamic acid during baking of the coating film.

< liquid Crystal alignment film >

< method for producing liquid Crystal alignment film >

The liquid crystal alignment film of the present invention is obtained by coating the liquid crystal alignment agent on a substrate, drying the coating, and baking the coating. The substrate to which the liquid crystal aligning agent of the present invention is applied is not particularly limited as long as it is a substrate having high transparency, and a plastic substrate such as a glass substrate, a silicon nitride substrate, an acrylic substrate, or a polycarbonate substrate can be used. In the reflective liquid crystal display element, an opaque material such as a silicon wafer may be used as long as it is a single-sided substrate, and a material that reflects light such as aluminum may be used as the electrode in this case.

Examples of the method for applying the liquid crystal aligning agent of the present invention include spin coating, printing, and ink jet methods. The drying and firing steps after the application of the liquid crystal aligning agent of the present invention can be performed at any temperature and for any time. In order to sufficiently remove the organic solvent contained therein, the organic solvent is usually dried at 50 to 120 ℃ for 1 to 10 minutes and then fired at 150 to 300 ℃ for 5 to 120 minutes. The thickness of the coating film after firing is not particularly limited, but if it is too thin, the reliability of the liquid crystal display element may be lowered, and therefore, it is 5 to 300nm, preferably 10 to 200 nm.

Examples of the method for aligning the liquid crystal alignment film include a brush rubbing method and a photo-alignment treatment method.

The brushing process can be performed using an existing brushing apparatus. Examples of the material of the brush polishing cloth in this case include cotton, nylon, rayon, and the like. The conditions for the brushing treatment are generally 300 to 2000rpm in rotation speed, 5 to 100mm/s in feed speed, and 0.1 to 1.0mm in pressing amount. Subsequently, the residue generated by the brushing is removed by ultrasonic cleaning using pure water, alcohol, or the like.

Specific examples of the photo-alignment treatment method include the following methods: and (c) irradiating the surface of the coating film with a radiation beam polarized in a predetermined direction, and optionally heating the coating film at a temperature of 150 to 250 ℃ to impart an alignment ability to the liquid crystal. As the radiation rays, ultraviolet rays and visible rays having a wavelength of 100nm to 800nm can be used. Among these, ultraviolet rays having a wavelength of 100nm to 400nm are preferable, and ultraviolet rays having a wavelength of 200nm to 400nm are particularly preferable. In addition, in order to improve the liquid crystal alignment, the coated substrate may be heated at 50 to 250 ℃ and irradiated with radiation. The irradiation amount of the radiation is preferably 1 to 10000mJ/cm ²Particularly preferably 100 to 5000mJ/cm². The liquid crystal alignment film prepared as described above can stably align liquid crystal molecules in a certain direction.

The higher the extinction ratio of polarized ultraviolet rays, the higher the anisotropy can be imparted, and therefore, the higher the extinction ratio is preferable. Specifically, the extinction ratio of the linearly polarized ultraviolet rays is preferably 10:1 or more, more preferably 20:1 or more.

The film irradiated with polarized radiation as described above may be subsequently subjected to a contact treatment with a solvent containing at least 1 selected from water and organic solvents.

The solvent used in the contact treatment is not particularly limited as long as it dissolves a decomposition product generated by light irradiation. Specific examples thereof include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, and cyclohexyl acetate. These solvents may be used in combination of 2 or more.

From the viewpoint of versatility and safety, at least 1 selected from the group consisting of water, 2-propanol, 1-methoxy-2-propanol, and ethyl lactate is more preferable. Particularly preferred are water, 2-propanol, and a mixed solvent of water and 2-propanol.

In the present invention, the contact treatment of the film irradiated with the polarized radiation and the solution containing the organic solvent is performed by a treatment which can preferably bring the film into sufficient contact with the liquid, such as a dipping treatment or a spraying (spray) treatment. Among them, a method of immersing the film in a solution containing an organic solvent for preferably 10 seconds to 1 hour, more preferably 1 to 30 minutes is preferable. The contact treatment may be performed at normal temperature or under heating, and is preferably performed at 10 to 80 ℃, more preferably at 20 to 50 ℃. Further, if necessary, means for improving the contact such as ultrasonic waves may be applied.

After the contact treatment, either or both of rinsing (rinsing) with a low boiling point solvent such as water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, or the like and drying may be performed to remove the organic solvent in the solution used.

Further, the film subjected to the contact treatment with the solvent may be heated at 150 ℃ or higher for drying the solvent and reorienting the molecular chains in the film.

The heating temperature is preferably 150 to 300 ℃. The higher the temperature, the more the reorientation of the molecular chain is promoted, but if the temperature is too high, the decomposition of the molecular chain may be accompanied. Therefore, the heating temperature is more preferably 180 to 250 ℃, and particularly preferably 200 to 230 ℃.

If the heating time is too short, the effect of reorienting the molecular chains may not be obtained, and if it is too long, the molecular chains may be decomposed, and therefore, it is preferably 10 seconds to 30 minutes, more preferably 1 minute to 10 minutes.

The obtained liquid crystal alignment film is easily dissolved in a reworkable material and has excellent reworkability.

Examples of the solvent used for the reprocessing include: glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and propylene glycol monomethyl ether; glycol esters such as methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether acetate, and propylene glycol propyl ether acetate; glycols such as diethylene glycol, propylene glycol, butylene glycol, and hexylene glycol; alcohols such as methanol, ethanol, 2-propanol, and butanol; ketones such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, and γ -butyrolactone; esters such as methyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl glycolate, methyl 2-hydroxy-3-methylbutyrate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl pyruvate, ethyl acetate, butyl acetate, ethyl lactate, and butyl lactate; amides such as N, N-dimethylformamide, N-dimethylacetamide and N-methyl-2-pyrrolidone.

As the reworking material, it is preferable that the solvent contains an alkaline component such as ethanolamine and a rust inhibitor so that the alkalinity does not damage other members such as electrodes. The manufacturer for providing such reworked materials includes Korea Hui Ming Industrial Co., Ltd., KPX chemical, etc.

The reprocessing is performed by the following steps: the reworked material mentioned above is immersed in the substrate with the liquid crystal alignment film at room temperature or after heating to 30 to 100 ℃ for 1 to 1000 seconds, preferably 30 to 500 seconds; or the reworked material is sprayed in a shower type, and then the liquid is removed and washed with an alcohol solvent or pure water. From the viewpoint of work efficiency, the temperature of the reprocessing liquid at the time of reprocessing is preferably low, and is usually room temperature to 60 ℃, and more preferably room temperature to 40 ℃.

< liquid Crystal display element >

The liquid crystal display element of the present invention is obtained as follows: after a substrate with a liquid crystal alignment film is obtained from the liquid crystal alignment agent of the present invention by the above-described method for producing a liquid crystal alignment film, a liquid crystal cell is prepared by a known method, and a liquid crystal display element is produced using the liquid crystal cell.

As an example of a method for manufacturing a liquid crystal cell, a liquid crystal display element having a passive matrix structure will be described as an example. Note that the liquid crystal display element may be an active matrix liquid crystal display element in which a switching element such as a TFT (Thin Film Transistor) is provided in each pixel portion constituting image display.

First, a transparent glass substrate is prepared, a common electrode is provided on one substrate, and segment electrodes are provided on the other substrate. These electrodes may be formed of, for example, ITO electrodes, and patterned so as to display a desired image. Next, an insulating film is provided on each substrate so as to cover the common electrode and the segment electrode. The insulating film may be made of, for example, SiO formed by a sol-gel method₂-TiO₂And (3) forming a film.

Next, the liquid crystal alignment film of the present invention is formed on each substrate by the above-described method.

Next, one substrate was stacked on the other substrate so that the alignment film surfaces thereof were opposed to each other, and the periphery was bonded with a sealant. In the sealant, a spacer is usually mixed in advance in order to control a substrate gap. In addition, it is preferable that spacers for controlling the substrate gap are dispersed in advance in the surface portion where the sealing agent is not provided. An opening capable of being filled with liquid crystal from the outside is provided in advance in a part of the sealant.

Next, a liquid crystal material was injected into the space surrounded by the 2 substrates and the sealant through the opening provided in the sealant. Then, the opening is sealed with an adhesive. The injection may be performed by a vacuum injection method or a method using a capillary phenomenon in the atmosphere. Next, the polarizing plate was disposed. Specifically, a pair of polarizing plates was attached to the surface of the 2-sheet substrate opposite to the liquid crystal layer. The liquid crystal display element of the present invention is obtained through the above steps.

In the present invention, as the sealant, for example, a resin having a reactive group such as an epoxy group, an acryloyl group, a methacryloyl group, a hydroxyl group, an allyl group, or an acetyl group, which is cured by ultraviolet irradiation or heating, can be used. In particular, a curable resin system having both an epoxy group and a (meth) acryloyl group is preferably used.

The sealant of the present invention may contain an inorganic filler for improving adhesiveness and moisture resistance. The inorganic filler that can be used is not particularly limited, and specifically includes spherical silica, fused silica, crystalline silica, titanium oxide, titanium black, silicon carbide, silicon nitride, boron nitride, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, magnesium oxide, zirconium oxide, aluminum hydroxide, calcium silicate, aluminum silicate, lithium aluminum silicate, zirconium silicate, barium titanate, glass fiber, carbon fiber, molybdenum disulfide, asbestos, and the like, and preferably spherical silica, fused silica, crystalline silica, titanium oxide, titanium black, silicon nitride, boron nitride, calcium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, aluminum hydroxide, calcium silicate, and aluminum silicate. The inorganic filler can be mixed with 2 or more.

Since the liquid crystal display element uses the liquid crystal alignment film obtained by the method for producing a liquid crystal alignment film of the present invention as a liquid crystal alignment film, the liquid crystal display element is excellent in reworkability and can be suitably used for a large-screen and high-definition liquid crystal television or the like.

Examples

The details of the production method of the present invention will be described below by referring to experimental methods for investigating the raw material composition and the compounding ratio, results thereof, and examples of typical production methods. The present invention is not limited to these examples.

Description of abbreviations used in the present embodiment

(organic solvent)

NMP: n-methyl-2-pyrrolidone

GBL: gamma-butyrolactone

BCS: butyl cellosolve

Acid dianhydride (a): the following formula (A)

Acid dianhydride (B): the following formula (B)

Acid dianhydride (C): the following formula (C)

Acid dianhydride (D): the following formula (D)

Acid dianhydride (E): the following formula (E)

DA-1: the following formula (DA-1)

DA-2: the following formula (DA-2)

DA-3: the following formula (DA-3)

DA-4: the following formula (DA-4)

DA-5: the following formula (DA-5)

DA-6: the following formula (DA-6)

DA-7: the following formula (DA-7)

DA-8: the following formula (DA-8)

DA-9: the following formula (DA-9)

DA-10: the following formula (DA-10)

AD-1: the following formula (AD-1)

AD-2: the following formula (AD-2)

The following description will be made of methods for measuring viscosity, imidization ratio, reworkability, production of liquid crystal cell, and charge relaxation property.

[ measurement of viscosity ]

In the synthesis examples, the viscosities of the polyamic acid ester and the polyamic acid solution were measured using an E-type viscometer TV-25H (manufactured by Toyobo Co., Ltd.) under conditions of a sample volume of 1.1mL, CORD-1(1 ℃ 34', R24), and a temperature of 25 ℃.

[ measurement of imidization ratio ]

20mg of the polyimide powder was put into an NMR sample tube (NMR sample tube Standard. phi.5, manufactured by Softweed scientific Co., Ltd.), 0.53ml of deuterated dimethyl sulfoxide (DMSO-d6, 0.05% TMS (tetramethylsilane) mixture) was added thereto, and the mixture was dissolved completely by applying ultrasonic waves. The solution was subjected to 500MHz proton NMR measurement using a NMR measuring instrument (JNW-ECA500) manufactured by electron DATUM of Japan. The imidization ratio was determined using a proton derived from a structure which did not change before and after imidization as a reference proton, and the peak integral value of this proton and the peak integral value of a proton derived from an NH group of amic acid appearing in the vicinity of 9.5ppm to 10.0ppm were used to obtain the ratio by the following formula.

Imidization ratio (%) - (1-. alpha.x/y). times.100

In the above formula, x is a peak integrated value of a proton derived from an NH group of amic acid, y is a peak integrated value of a reference proton, and α is a number ratio of the reference proton to 1 NH group proton of amic acid in the case of polyamic acid (imidization ratio of 0%).

[ evaluation of reworkability ]

The liquid crystal aligning agent of the present invention is coated on an ITO substrate by a spin coating method. After drying on a hot plate at 60 ℃ for 1 minute and 30 seconds, the film was baked in a hot air circulating oven at 230 ℃ for 20 minutes to form a coating film having a thickness of 100 nm. Then, the prepared substrate was immersed in the heated reworked material for 300 seconds and developed, and then washed with running water with ultrapure water for 20 seconds. Then, air blowing was performed, evaluation was performed according to the following criteria, and the obtained results are shown in table 4.

O: no residual film at 35 deg.C for 5 min

And (delta): no residual film at 40 deg.C for 5 min

X: residual film at 40 deg.C for 5 min

[ production of liquid Crystal cell ]

A liquid crystal cell having a Fringe Field Switching (hereinafter, referred to as FFS) mode liquid crystal display element structure was prepared.

First, a substrate with an electrode is prepared. The substrate was a glass substrate having dimensions of 30mm × 35mm and a thickness of 0.7 mm. On the substrate, as the 1 st layer, an ITO electrode having a solid pattern for constituting a counter electrode was formed. On the counter electrode of the 1 st layer, a SiN (silicon nitride) film formed by a CVD method was formed as a 2 nd layer. The SiN film of the 2 nd layer has a film thickness of 500nm and functions as an interlayer insulating film. On the SiN film of the 2 nd layer, a comb-shaped pixel electrode formed by patterning an ITO film is disposed as a 3 rd layer, and two pixels, i.e., a 1 st pixel and a 2 nd pixel, are formed. The size of each pixel was 10mm in length and 5mm in width. At this time, the counter electrode of the 1 st layer and the pixel electrode of the 3 rd layer are electrically insulated by the SiN film of the 2 nd layer.

The pixel electrode of the 3 rd layer has a comb-tooth shape formed by arranging a plurality of "く" shaped electrode elements with bent central portions. The width of each electrode element in the width direction was 3 μm, and the interval between the electrode elements was 6 μm. Since the pixel electrode forming each pixel is formed by arranging a plurality of "く" -shaped electrode elements each having a bent central portion, each pixel has a shape similar to a bold "く" -shaped electrode element, which is bent at the central portion in the same manner as the electrode elements, instead of a rectangular shape. Each pixel is divided vertically with a curved portion at the center as a boundary, and has a 1 st region on the upper side and a 2 nd region on the lower side of the curved portion.

When comparing the 1 st region and the 2 nd region of each pixel, the forming directions of the electrode elements constituting the pixel electrodes are different. That is, when the brushing direction of the liquid crystal alignment film described later is set as a reference, the electrode elements of the pixel electrode are formed so as to form an angle of +10 ° (clockwise) in the 1 st region of the pixel, and the electrode elements of the pixel electrode are formed so as to form an angle of-10 ° (clockwise) in the 2 nd region of the pixel. That is, the 1 st region and the 2 nd region of each pixel are configured as follows: the directions of the rotational movement (planar switching) of the liquid crystal in the substrate plane induced by applying a voltage between the pixel electrode and the counter electrode are opposite to each other.

Next, the obtained liquid crystal aligning agent was filtered with a 1.0 μm filter, and then applied onto the prepared electrode-carrying substrate and the glass substrate having the ITO film formed on the back surface thereof and the columnar spacer having a height of 4 μm by a spin coating method. After drying on a hot plate at 80 ℃ for 5 minutes, the resultant was baked in a hot air circulating oven at 230 ℃ for 20 minutes to form a coating film having a thickness of 100 nm. The coated surface is subjected to alignment treatment such as brushing and polarized ultraviolet irradiation to obtain a substrate with a liquid crystal alignment film. The two substrates were used as a set, a sealant was printed on the substrates, and the other substrate was bonded so that the liquid crystal alignment films face each other and the alignment direction was 0 °, and then the sealant was cured to prepare an empty cell. Liquid crystal MLC-2041 (manufactured by MERCK) was injected into the empty cell by a reduced pressure injection method, and the injection port was sealed to obtain an FFS-driven liquid crystal cell. Subsequently, the resulting liquid crystal cell was heated at 110 ℃ for 1 hour, left overnight, and then used for each evaluation.

[ evaluation of Charge relaxation Properties ]

The liquid crystal cell was placed on a light source, and after the V-T characteristic (voltage-transmittance characteristic) at room temperature was measured, the transmittance (Ta) of the liquid crystal cell in a state where a rectangular wave of ± 1.5V/60Hz was applied was measured. Subsequently, the transmittance (Tb) of the liquid crystal cell was measured while superimposing direct current 1V and driving for 30 minutes, the direct current voltage was cut off, the transmittance (Tc) of the liquid crystal cell was measured when driving again only with a rectangular wave of ± 1.5V/60Hz for 20 minutes, and the difference (Δ T) in transmittance due to the voltage remaining in the liquid crystal display element was calculated from the difference (Δ T) between the transmittance (Tb, Tc) at each time and the initial transmittance (Ta). It is considered that the earlier the residual voltage is relaxed, the less afterimage is generated. When the DC voltage was started for 5 minutes, (Tb-Ta) was rated as O at 2% or less and rated as X at least, and when the DC voltage was cut off for 5 minutes, (Tc-Ta) was rated as O at 2% or less and rated as X at least. The results are shown in Table 4.

Polymerization example 1

A1L four-necked flask equipped with a stirrer was placed in a nitrogen atmosphere, 86.0g of (DA-4), (DA-7)53.4g, and (DA-10)76.5g were taken, and NMP 1580g was added and dissolved at 23 ℃ with stirring while feeding nitrogen. To the diamine solution, while stirring, 93.2g of acid dianhydride (E) and 168g of NMP were added, and the mixture was stirred at 40 ℃ for 3 hours under a nitrogen atmosphere. 28.2g of acid dianhydride (D) was added, 160g of NMP was further added, and the mixture was stirred at 23 ℃ for 4 hours under a nitrogen atmosphere to obtain a polyamic acid solution (PAA-1). The polyamic acid solution had a viscosity of 200 mPas at a temperature of 25 ℃.

20.4g of the polyamide powder was taken out from a 300mL Erlenmeyer flask containing a stirrer, NMP150g was added thereto, and the mixture was stirred at 50 ℃ for 20 hours to dissolve the powder, thereby obtaining a polyimide solution (SPI-1).

20.4g of the polyamide powder was taken out from a 300mL Erlenmeyer flask containing a stirrer, NMP150g was added, and the mixture was stirred at 50 ℃ for 20 hours to dissolve the polyamide powder. Further, 16.3g of this solution was taken out from a 100mL Erlenmeyer flask equipped with a stirrer, and 3.46g of NMP, 13.0g of GBL, 1.95g of an NMP solution containing 1 mass% of 3-glycidoxypropyltriethoxysilane, and 8.69g of BCS were added thereto, followed by stirring with a magnetic stirrer for 2 hours to obtain a polyimide solution (SPI-1).

(polymerization example 2)

A100 mL four-necked flask equipped with a stirrer was placed in a nitrogen atmosphere, and 42.8g of NMP was added to 0.58g of (DA-6), (DA-4)1.32g, (DA-5)0.93g, and (DA-7)3.01g of (DA-6), and the mixture was dissolved at 23 ℃ with stirring while feeding nitrogen. To this diamine solution, 3.91g of acid dianhydride (E) and 12.4g of NMP were added while stirring, and the mixture was stirred at 40 ℃ for 16 hours under a nitrogen atmosphere to obtain a polyamic acid solution (PAA-2). The polyamic acid solution has a viscosity of 450cps at a temperature of 25 ℃.

(polymerization example 3)

A100 mL four-necked flask equipped with a stirrer was placed in a nitrogen atmosphere, 6.19g of (DA-9) and 2.14g of (DA-8) were taken, 61.1g of NMP was added thereto, and the mixture was dissolved at 23 ℃ with stirring while feeding nitrogen. While stirring this diamine solution, 5.71g of acid dianhydride (B) and 18.5g of NMP were added, and the mixture was stirred at 50 ℃ for 16 hours under a nitrogen atmosphere to obtain a polyamic acid solution (PAA-3). The polyamic acid solution had a viscosity of 351cps at a temperature of 25 ℃.

Polymerization example 4

A50 mL four-necked flask equipped with a stirrer was placed in a nitrogen atmosphere, 2.55g of (DA-1) and 0.78g of (DA-4) were taken, 24.4g of NMP was added thereto, and the mixture was dissolved at 23 ℃ with stirring while feeding nitrogen. While stirring this diamine solution, 1.75g of acid dianhydride (B) was added, 4.3g of NMP was further added, and the mixture was stirred at 23 ℃ for 2 hours under a nitrogen atmosphere, and then 1.41g of acid dianhydride (D) was added, 8.0g of NMP was further added, and the mixture was stirred at 23 ℃ for 2 hours under a nitrogen atmosphere. Then, the mixture was stirred at 50 ℃ for 16 hours to obtain a polyamic acid solution (PAA-4). The polyamic acid solution has a viscosity of 240cps at a temperature of 25 ℃.

Polymerization example 5

A50 mL four-necked flask equipped with a stirrer was placed in a nitrogen atmosphere, 2.55g of (DA-1) and 0.96g of (DA-3) were taken, 25.7g of NMP was added thereto, and the mixture was dissolved at 23 ℃ with stirring while feeding nitrogen. While stirring this diamine solution, 3.00g of acid dianhydride (C) and 11.2g of NMP were added, and the mixture was stirred at 23 ℃ for 2 hours under a nitrogen atmosphere, 0.77g of acid dianhydride (D) and 4.4g of NMP were added, and the mixture was stirred at 23 ℃ for 2 hours under a nitrogen atmosphere. Then, the mixture was stirred at 50 ℃ for 16 hours to obtain a polyamic acid solution (PAA-5). The polyamic acid solution has a viscosity of 358cps at a temperature of 25 ℃.

Polymerization example 6

A50 mL four-necked flask equipped with a stirrer was placed in a nitrogen atmosphere, 2.55g of (DA-1) and 0.46g of (DA-2) were taken, 22.3g of NMP was added thereto, and the mixture was dissolved at 23 ℃ with stirring while feeding nitrogen. While stirring this diamine solution, 2.00g of acid dianhydride (C) and 6.3g of NMP were added, and the mixture was stirred at 23 ℃ for 2 hours under a nitrogen atmosphere, 1.51g of acid dianhydride (D) and 8.5g of NMP were added, and the mixture was stirred at 23 ℃ for 2 hours under a nitrogen atmosphere. Then, the mixture was stirred at 50 ℃ for 16 hours to obtain a polyamic acid solution (PAA-6). The polyamic acid solution had a viscosity of 333cps at a temperature of 25 ℃.

Polymerization example 7

A50 mL four-necked flask equipped with a stirrer was placed in a nitrogen atmosphere, 2.55g of (DA-1) and 0.46g of (DA-2) were taken, 22.3g of NMP was added thereto, and the mixture was dissolved at 23 ℃ with stirring while feeding nitrogen. While stirring this diamine solution, 4.5g of acid dianhydride (A) and 20.5g of NMP were added, and the mixture was stirred at 23 ℃ for 2 hours and then at 50 ℃ for 16 hours under a nitrogen atmosphere to obtain a polyamic acid solution (PAA-7). The polyamic acid solution has a viscosity of 350cps at a temperature of 25 ℃.

Polymerization example 8

A50 mL four-necked flask equipped with a stirrer was placed in a nitrogen atmosphere, 2.55g of (DA-1) and 0.49g of (DA-2) were taken, 22.3g of NMP was added thereto, and the mixture was dissolved at 23 ℃ with stirring while feeding nitrogen. While stirring this diamine solution, 3.00g of acid dianhydride (C) and 12.0g of NMP were added, and the mixture was stirred at 23 ℃ for 2 hours under a nitrogen atmosphere, 0.72g of acid dianhydride (D) and 4.1g of NMP were added, and the mixture was stirred at 23 ℃ for 2 hours under a nitrogen atmosphere. Then, the mixture was stirred at 50 ℃ for 16 hours to obtain a polyamic acid solution (PAA-8). The polyamic acid solution had a viscosity of 333cps at a temperature of 25 ℃.

Comparative example 1

7.00g of the polyimide solution (SPI-1) obtained above, (PAA-4)10.40g, 2.40g of an NMP solution containing 1 wt% (AD-1) and 0.72g of an NMP solution containing 10 wt% (AD-2) were taken out from a 50mL Erlenmeyer flask equipped with a stirrer, and 7.48g of NMP and 12.00g of BCS were added thereto and stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal aligning agent (A-1).

Comparative example 2

6.73g of the polyamic acid solution (PAA-2), 15.27g of (PAA-5), 2.40g of an NMP solution containing 1 wt% (AD-1), and 0.72g of an NMP solution containing 10 wt% (AD-2) were taken out from a 50mL Erlenmeyer flask equipped with a stirrer, and 2.88g of NMP and 12.00g of BCS were added thereto, followed by stirring with a magnetic stirrer for 2 hours to obtain a liquid crystal aligning agent (A-2).

Comparative example 3

4.00g of the polyamic acid solution (PAA-3) obtained in comparative synthesis example, 12.80g of (PAA-6), and 2.40g of a 1 wt% (AD-1) -containing NMP solution were taken out from a 50mL Erlenmeyer flask equipped with a stirrer, and 8.80g of NMP and 12.00g of BCS were added thereto, followed by stirring with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (A-3).

(examples 1 to 2)

7.00g of polyimide solution (SPI-1) was charged into a 50mL Erlenmeyer flask equipped with a stirrer, and (PAA-6) and (PAA-7) obtained in the polymerization example were added in the manner shown in Table 1, and then 2.40g of NMP solution containing 1 wt% (AD-1) and 0.72g of NMP solution containing 10 wt% (AD-2) were separated, and 7.48g of NMP and 12.00g of BCS were added thereto, and stirred with a magnetic stirrer for 2 hours to obtain liquid crystal alignment agents (B-1 to 2) shown in Table 1.

[ Table 1]

(examples 3 to 6)

4.00g of polyamic acid solution (PAA-3) was added to a 50mL Erlenmeyer flask equipped with a stirrer, and the polyamic acid solutions (PAA-6 to 8) obtained in the polymerization examples were added in the manner shown in Table 2, and then 2.40g of NMP solution containing 1 wt% (AD-1) was separated, 4.80g of NMP and 12.00g of BCS were added thereto, and the mixture was stirred with a magnetic stirrer for 2 hours to obtain liquid crystal alignment agents (B-3 to 6) shown in Table 2.

[ Table 2]

(examples 7 to 8)

6.73g of the polyamic acid solution (PAA-2) obtained in comparative synthesis example was charged into a 50mL Erlenmeyer flask equipped with a stirrer, and the polyamic acid solutions (PAA-5) and (PAA-7) obtained in polymerization example were added in the manner shown in Table 3, and then 2.40g of an NMP solution containing 1 wt% (AD-1) and 0.72g of an NMP solution containing 10 wt% (AD-2) were taken out separately, and 2.88g of NMP and 12.00g of BCS were added, followed by stirring with a magnetic stirrer for 2 hours to obtain a liquid crystal aligning agent (A-2).

[ Table 3]

[ Table 4]

Industrial applicability

The liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention reduces charge accumulation due to asymmetry of ac drive in liquid crystal display elements of IPS drive system and FFS drive system, and quickly alleviates residual charge accumulated by dc voltage, so that liquid crystal display elements of IPS drive system and FFS drive system having excellent image sticking characteristics can be obtained. Therefore, the liquid crystal alignment film is particularly useful as a liquid crystal display element of an IPS driving method or an FFS driving method, or a liquid crystal alignment film of a liquid crystal television.

Claims

1. A liquid crystal aligning agent, comprising:

(A-2) at least 1 polymer selected from the group consisting of polyamic acid obtained by using a tetracarboxylic dianhydride component containing an aliphatic tetracarboxylic dianhydride and a diamine component containing a diamine represented by the following formula (2), and an imidized polymer of the polyamic acid;

an organic solvent, and a solvent mixture comprising an organic solvent,

in the formula (1), i is 0 or 1, X is a single bond, an ether bond, a carbonyl group, an ester bond, a phenylene group, a linear alkylene group with 1 to 20 carbon atoms, a branched alkylene group with 2 to 20 carbon atoms, a cyclic alkylene group with 3 to 12 carbon atoms, a sulfonyl group, an amide bond or a group formed by combining the two, wherein the alkylene group with 1 to 20 carbon atoms is optionally interrupted by a bond selected from the ester bond and the ether bond, and the carbon atoms of the phenylene group and the alkylene group are optionally substituted by 1 or more same or different substituents selected from a halogen atom, a cyano group, an alkyl group, a halogenated alkyl group, an alkoxy group and a halogenated alkoxy group,

in the formula (2), Y₁Is a 2-valent organic group having at least 1 structure selected from the group consisting of amino groups, imino groups and nitrogen-containing heterocyclic rings, B ₁、B₂Each independently represents a hydrogen atom, or an optionally substituted alkyl, alkenyl or alkynyl group having 1 to 10 carbon atoms,

the tetracarboxylic dianhydride represented by the formula (1) is 3,3 ', 4, 4' -biphenyltetracarboxylic dianhydride,

in the component (A-1), the amount of the tetracarboxylic dianhydride represented by the formula (1) is 10 to 100 mol% based on 1 mol of the total tetracarboxylic dianhydride used for producing the component (A-1), the proportion of the diamine represented by the formula (2) is 10 to 100 mol% based on 1 mol of the total diamine used for producing the component (A-1), the amount of the aliphatic tetracarboxylic dianhydride in the component (A-2) is 10 to 100 mol% based on 1 mol of the total tetracarboxylic dianhydride used for producing the component (A-2), and the proportion of the diamine represented by the formula (2) is 10 to 100 mol% based on 1 mol of the total diamine used for producing the component (A-2).

2. The liquid crystal aligning agent according to claim 1, wherein 10 to 100 mol% of the tetracarboxylic dianhydride component of the (A-1) is the tetracarboxylic dianhydride represented by the formula (1).

3. The liquid crystal aligning agent according to claim 1, wherein 10 to 100 mol% of the tetracarboxylic dianhydride component (A-2) is an aliphatic tetracarboxylic dianhydride.

4. The liquid crystal aligning agent according to any one of claims 1 to 3, wherein 10 to 100 mol% of the diamine component of (A-1) and (A-2) is a diamine of formula (2).

5. The liquid crystal aligning agent according to any one of claims 1 to 3, wherein Y in the formula (2)₁Is at least 1 selected from the following structures of formulas (YD-1) to (YD-5),

in the formula (YD-1), A₁Is a nitrogen atom-containing heterocycle having 3 to 15 carbon atoms, Z₁A hydrogen atom or an optionally substituted hydrocarbon group having 1 to 20 carbon atoms; in the formula (YD-2), W₁Is a C1-10 hydrocarbon group, A₂Is a C3-15 organic group having a nitrogen atom-containing heterocycle, or a disubstituted amino group substituted with a C1-6 aliphatic group; in the formula (YD-3), W₂A C6-15 and a 2-valent organic group having 1-2 benzene rings, W₃Is alkylene or biphenylene having 2 to 5 carbon atoms, Z₂Is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a benzene ring, and a is an integer of 0 to 1; in the formula (YD-4), A₃Is a nitrogen atom-containing heterocycle having 3 to 15 carbon atoms; in the formula (YD-5), A₄Is a C3-15 nitrogen atom-containing heterocycle, W₅Is an alkylene group having 2 to 5 carbon atoms.

6. The liquid crystal aligning agent according to claim 5, wherein A is represented by the formulae (YD-1), (YD-2), (YD-4) and (YD-5) ₁、A₂、A₃And A₄Is at least 1 selected from the group consisting of pyrrolidine, pyrrole, imidazole, pyrazole, oxazole, thiazole, piperidine, piperazine, pyridine, pyrazine, indole, benzimidazole, quinoline, and isoquinoline.

7. The liquid crystal aligning agent according to any one of claims 1 to 3, wherein Y in the formula (2)₁Is selected fromAt least 1 kind of 2-valent organic group with the following formulas (YD-6) to (YD-21),

in the formula (YD-17), h is an integer of 1 to 3, and in the formulae (YD-14) and (YD-21), j is an integer of 1 to 3.

8. The liquid crystal aligning agent according to claim 7, wherein Y in the formula (2)₁Is at least 1 selected from the group consisting of 2-valent organic groups having the structures of the above-described formulae (YD-14) and (YD-18).

9. The liquid crystal aligning agent according to any one of claims 1 to 3, wherein the aliphatic tetracarboxylic dianhydride is bicyclo [3.3.0] octane 2,4,6, 8-tetracarboxylic acid 2,4:6,8 dianhydride.

10. A liquid crystal alignment film obtained by applying the liquid crystal aligning agent according to any one of claims 1 to 9 and firing the applied liquid crystal aligning agent.

11. A liquid crystal display element comprising the liquid crystal alignment film according to claim 10.